Emission Compliant Fuel and Exhaust Systems

The auto industry is gearing up to meet the accelerated emission compliance challenges posed by the government. Even the refineries have to deliver BS-VI compliant fuel to enable implementation.

India’s decision to leapfrog to BS-VI emission norms by 2020 has spurred the development of new generation fuel and exhaust management systems, also termed as “Clean Air Systems”. However, the success or failure of the proposed compliance norms will also largely depend on availability of emission-compliant fuel to be delivered by Indian refineries. As such, it is a national challenge and all stakeholders are gearing up their respective acts to deliver.

With major cities in India struggling with air quality issues, the Indian government in February 2016 decided to leapfrog the Bharat Stage (BS) V Emission Standards and directly move to the more stringent BS-VI norms by April 2020, four years ahead of the earlier schedule. Globally, emission standards have been implemented in a phased manner with adequate time gap (typically 45 years) between two levels. We believe while availability of technology is unlikely to be a deterrent, the key challenge for OEMs will be in adapting the available solutions to Indian market conditions in a relatively short time-frame, while making them cost-effective.

Further, given the past experience with respect to delays in availability of BS-IV compliant fuel, the availability of even more cleaner fuel by 2020 on a nationwide basis may also become a bottleneck. Our interaction with industry participants suggests that investments by OEMs are unlikely to be sizeable to meet BS-VI norms; however, OEMs with higher dependence on diesel models may accelerate their focus on the petrol segment, while hybrids and other clean technologies would take centre-stage in their R&D plans. Overall, the proposed emission standards will push vehicle prices upwards, with the diesel segment likely to witness sizeable cost increase due to introduction of additional components. This would make diesel Passenger Vehicles (PVs) costlier (vis à-vis petrol variants) and consequently may deter demand for diesel PVs.

The Government of India has recently released the proposed draft for implementation of revised emission norms, inviting all the stakeholders to present their comments, point of views and suggestions. Subsequently, the final draft will be placed in Parliament for debate and passing of a formal

Salient Features of Proposed BS-VI Norms

The proposed BS-VI norms would align India to European regulations by 2020 in all segments except three-wheelers. With major cities in India struggling with severe air-quality problems, the Indian government recently proposed to leapfrog BS-V emission standards and directly move to the more stringent BS-VI norms by April 2020. Unlike the earlier norms, the proposed emission standards would be implemented simultaneously across the country and will cover even the two- and three-wheeler segments.

With this proposal, the emission standards for automobiles in India will effectively move from BS-III and BS-IV (at present) to BS-VI in a matter of approximately four years, which will be the first global instance of skipping an intermediate emission level. Globally, most of the key automobile markets have upgraded the emission norms in a phased manner, with typically time gap of four-five years between two levels.

In comparison to existing emission standards, the proposed BS-VI norms incorporate substantial tightening of Nitrogen Oxide (NOx) and Particulate Matter (PM) and also implement a limit on Particle Number (PN). Further, the emission standards are incrementally far more stringent for diesel vehicles as compared to petrol variants.

The other noteworthy aspect of the BS-VI standard is the shift towards real-world driving cycles for evaluation of emission levels in light duty vehicles (which will cover PVs and SCVs) and World Harmonised Steady Cycle (WHSC) & World Harmonised Transient Cycle (WTSC) for heavy-duty vehicles (primarily trucks & buses). These testing cycles are more representative of real-world driving conditions and are able to better capture driving modes when emission levels are elevated.

Emission norms are incrementally more stringent for diesel vehicles; OBD requirements also increased.

In addition, the proposed BS-VI norms also incorporate enhanced On-Board Diagnostics (OBD) requirements for all vehicle segments. Interestingly, the two- and three-wheelers will also be required to implement OBD for the first time ever. More importantly, the emission norms for two-wheelers (i.e., CO, HC & NOx) will become equivalent to proposed BS-VI norms for petrol-driven PVs, thereby implying that BS-VI two-wheelers will be as clean as petrol PVs.

As mentioned earlier, the proposed emission norms incrementally are far more stringent for diesel vehicles when compared to their petrol variants. For instance, the proposed norms mandate a reduction of 68 per cent and 82 per cent in NOx and PM levels in diesel vehicles vis-à-vis BS-IV norms. In comparison, the NOx levels in petrol vehicles are required to drop by 25 per cent vis-à-vis the current BS-IV norms.

With proposed BS-VI emission standards being incrementally more stringent for diesel vehicles vis-à-vis petrol vehicles, the technology for the former is likely to undergo significant upgradation, both within the engine as well as the exhaust system. For instance, the sharp reduction in NOx levels can be achieved through introduction of new technologies such as Lean NOx Trap (LNT) (for diesel PVs) and Selective Catalytic Reduction (SCR) (for M&HCVs). In addition, Diesel Particulate Filters (DPFs) would emerge as the most common solution to control PM emissions from diesel PVs, MCVs and HCVs.

Unlike diesel vehicles, the adherence to BSVI norms for petrol vehicles can be achieved through improvement in a) air-fuel management (within the engine) and b) Exhaust Gas Recirculation (within the exhaust system) To clarify the statement, for petrol passenger cars: Improved version of MPFI & Three Way Catalytic Converter; Engine downsizing or Combustion –Gasoline Direct Injection and Exhaust–Gasoline Particulate Filter
For two-wheelers: it would entail that for Combustion –Electronic Fuel Injection (EFI); Exhaust–Three Way Catalytic Converter, Lean NOx trap (LNT); for Diesel additional Diesel oxidation catalysts (DOC), will be required
In reference to hybrid/electric assist vehicles, it is noteworthy that they experience almost no delay in power from a stop, due to the instant availability of power from the traction battery to the electric motor(s). Gasoline/micro hybrids on the other hand, generally experience slight delays (albeit fractions of a second).

Unlike all developed countries, ‘start-stop’ traffic conditions prevail in all Indian metro cities (and even Tier-II & III ones) are yet another challenge for the auto industry. Many people think that long-term use may induce additional wear due to lack of oil lubrication, and this is true. For the crankshaft bearing half shells and the big end bearings, this can translate into frequent high-speed rotary movement before a hydrodynamic film is established. During this phase of boundary lubrication, metal-to-metal contact can occur between the crankshaft surface and the bearing’s sliding surface. This was not an issue while the number of engine restarts totaled at what was generally understood to be a normal magnitude. However, in a vehicle with start-stop system, this effect can necessitate new technological solutions to avoid premature bearing wear, depending on the driving cycle. Consequently, future engines for start-stop applications need to be designed for 250,000 to 300,000 starts. Traditional bearing shells with aluminum or copper lining show severe wear after only 100,000 cycles. In a start-stop system, the short stop times keep the engine and oil warm, retaining lubrication. Some implementations do not use a starter motor, eliminating concerns of starter motor wear. Further, start-stop systems are heavily reliant on the battery. Testing indicates that AGM batteries diminish in their ability to support start-stop functionality over time.

Way Forward

For some industry stakeholders, it is good news, because they were already supplying products in line with Euro VI standards, for their overseas markets. Others need to accelerate and ramp up their respective technologies to meet the projected market demand of such components and vehicles, within a short span of less than four years.

Going beyond emissions, the recent crash tests conducted by GNCAP showed many cars to be having zero safety ratings. Currently, NCAP is allowing voluntary crash tests to be conducted under their specifications and permitting the manufacturers to advertise the results. Come 2019, crash tests will become mandatory for all vehicles. That’s one more worrisome aspect automakers have to work on.

It would be appropriate to mention that there is always a cost attributed to new technology. In this case, on one side, the vehicles have to be
made emission compliant through introduction of various systems described earlier. On the other hand, vehicles have to retain or improve their fuel economy in real time measurable, certifiable and transparent terms. Otherwise the Damocles’ sword of Dieselgate, Suzuki, Mitsubishi and other scandals hangs on their heads.

At present, two-wheelers follow BS-III norms, and are expected to migrate to BS-IV norms by April’17.

By April 2020, the two-wheeler segment will also be required to comply with BS-VI norms; this will mandate a shift in technology from carburetor to an Electronic Fuel Injection (EFI) system.

More importantly, the emission norms for two-wheelers (i.e., CO, HC & NOx) will become equivalent to proposed BS-VI norms for petrol-driven PVs.

Three-wheelers

The three-wheeler segment in India is also currently at BS-III norms and is expected to move to BS-IV standards by April 2017.

By April 2020, it will also move to BS-VI norms and will see sizeable changes in technology, particularly in diesel vehicles.

According to industry experts, the proposed BS-VI norms for three-wheelers are relatively less stringent than Euro-5 standards for similar vehicle category, though should provide meaningful emission reduction, relative to BS-III standards.